The Radiosensitizing Effects Of Free 17AAG And 17AAG Loaded Micelle On Non-small-cell Lung Cancer Cells

PurposeThis study investigated the radio-sensitizing effects of 17 AAG on human Non-small-cell carcinoma cells. As a targeting drug nano-carrier system, whether the polymeric micelles had a superior performance of better anticancer efficacy than free17 AAG and then discussed the possible mechanisms of these effects.Methods and MaterialsThe MTT assay was used to quantify the different growth inhibition of A549 cells between free 17 AAG and 17 AAG polymeric micelles. Using Multitarget-single hitting model fitting equation to analyze the radio-sensitizing effects caused by the drug.Herein, we used cell cycle、immunofluorescence、Senescence β-Galactosidase Staining and western-blot and animal model experiences. Using 17-allyamino-17-demethoxygeldanamycin(17-AAG) loaded polymeric mixed micelles, which solved the solubility problem of poorly-soluble drugs, in combination with X-ray to investigate the inhibition effect on non-small-cell lung cancer(NSCLC) cells.Results1) MTT assay demonstrate that the suppression of free-17 AAG and 17AAG-M were both in the dose-independent and time-independent. The cytotoxic effect of17AAG-M was much higher than free 17 AAG. The colony forming assay showed thatefficiency of 17AAG-M had a much more significantly radiosensitivity effect on the NSCLC cell lines.2) Senescence experiments showed an obvious aging phenomenon after the treatment of 17AAG-M combined with X-Ray and the cytotoxicity was in the dose-dependent. According to statistical results, the proportion of trigger cell aging of17AAG-M are higher than free 17 AAG in each dose point.3) Immunofluorescence analysis observed that 17AAG-M combined with X-Ray can obviously increase the DNA-damage sites and delay the DNA damage repair,which was notably different with free 17 AAG.4) 17AAG-M and free 17 AAG both inhibited the ERK kinase phosphorylation the Ras/Raf/ MAPK pathways’ ERK kinase phosphorylation, which make the MAPK pathway block.5) In nude mice animal model experience, free 17 AAG and 17AAG-M both inhibited A549 tumor growth significantly, but didn’t present a notably difference between the inhibiting effects.ConclusionsThe vitro experiences indicate that 17AAG-M get higher inhibition efficiency of the human non-small-cell carcinoma cells than free 17 AAG. The mechanism might be inducing the cell aging and delaying the DNA damage repair.Western blot indicated that MAPK pathway blocking might be a possible reason. 17 AAG and 17AAG-M act as powerful applied tools for chemotherapy in animal experiments.